Heany graduated from Sanglamore Academy, the second-most respected military academy in the Lyran Commonwealth.[1] The progression of her career suggests that she was born to a prestigious family, and may have hailed from the Federation of Skye region of the Commonwealth. Heany's career in the LCAF apparently progressed well, and at some point (apparently prior to her command of the 4th Skye Rangers) she was a regimental commander in the Lyran Guards.[2]

By 3025, she held the rank of Hauptmann-Kommandant, commanding the elite 4th Skye Rangers on Ryde.[3] The Fourth's quality and performance during this time was acknowledged even by their enemies in the Draconis Combine Mustered Soldiery, although Heany's own performance was described as "spotty".[4] Kuritan reports of Lyran female officers were typically biased though.

In the buildup to the Fourth Succession War, conventional regiments were permanently attached to the Fourth Rangers, officially making them an Regimental Combat Team, the same formation that had proved so successful for the allied House Davion. In addition, AFFS officers were brought in to "advise" Lyran units in the field, particularly in combined-arms tactics.[5] A Lightning Company was also attached to the regiment, composed of light and medium BattleMechs and staffed by warriors who had been trained in mobile tactics in the Federated Suns so they could take advantage of their superior mobility.[6][7] None of this seemed to be met with approval by the traditionalist Heany, who preferred the standard Lyran practice of direct assaults with the heaviest 'Mechs available.

Heany's Fourth Skye Rangers, along with twenty-five conventional regiments, were assigned to invade Marfik. Though a valuable world in and of itself, Marfik was defended by the 11th Legion of Vega, commanded by Tai-saTheodore Kurita, the Heir-designate of the Draconis Combine. The Eleventh Legion of Vega was a punishment assignment for him because of a falling-out with his father. Supported by twelve supporting regiments, it was composed of the dregs of the Combine military, castoffs and malcontents using inferior, second-hand equipment, and it was believed the superior quality of the Fourth, combined with the AFFS tactics and plans, would be more than enough to easily crush the defenders and claim Theodore Kurita as a prize.[8]

Heany's failure to capture Theodore Kurita was the pivotal moment in her career.

Capturing Kurita, the only son of CoordinatorTakashi Kurita, could potentially devastate the Combine for years to come. So determined were the Lyrans to trap the Dragon's heir on the planet that they used a Pirate Jump Point, quickly making planet-fall and seemingly reducing the chance for Kurita to make his escape.[9] The original battle plan had called for joint use of 'Mechs, infantry and armor against the Legion. However, when the Eleventh were not at Netaltown, as Davion Intelligence had expected, but were still in Massingham, Heany abandoned that strategy and ignored all AFFS advice. Leaving her armor and infantry behind, she lead her heavy and assault 'Mechs in a direct, frontal attack on the Eleventh in the Massingham valley on 29 August, 3028. Kurita responded by leading his second battalion in a charge, all the while his own support regiments were withdrawing into DonnerBrau forest. The charge was a feint, designed to buy the DCMS forces enough time to escape. The Legion withdrew into the forest in good order, though twelve 'Mechs were lost against the heavier machines of the Rangers. Heany overconfidantly ordered her 'Mechs to pursue, where her slower machines and lack of knowledge of the terrain soon led her forces to become lost, having lost contact with the Legion.[10][11][12][13] Meanwhile, Kurita led his Legion 'Mechs against the unprotected support regiments in Gether's Jewel. Still leading second battalion, Kurita wiped out several Lyran conventional regiments though he faced heavy resistance from the elite 13th Assault Regiment, who bought the remaining Lyran forces enough time to take up defensive positions. The Legion then pulled back, having seriously bloodied the Lyrans.[13][14][15]

After this, Heany reluctantly returned to the original strategy, including her conventional forces in the campaign and using aerospace fighters to help track the Legion down. This proved effective, and the Rangers slowly began pushing the Kuritan forces further east on the North Galfree continent. Clashes between the two sides were brief, as the numbers and quality of the Fourth Rangers took a toll on the Eleventh Legion, which was running low on supplies and spare parts to keep their equipment operational. Theodore Kurita, for his part, did a masterful job keeping his force intact, using guerilla warfare tactics and repeatedly striking at the Lyrans and fading away back into the forest.[16]

By 26 September, the battlefield losses and lack of supplies had forced the Legion and supporting units to prepare for their last stand in the hills of Sitika, a small coastal city. The Rangers and their own troops had been damaged, but had the overwhelming advantage in numbers, supplies, territory and air support.[17][18] The following day, Heany personally commanded the attacks. The Legion seemed to be holding its remaining 'Mechs in reserve, even as the Lyrans used 'Mechs, armor, infantry and aerospace support to push the Combine troops back. In fact, most of the supposed remaining Legion 'Mechs were harmless scrap metal mock-ups. The real 'Mechs only appeared when Lyran armor breached the Legion's lines. When Heany spotted Tai-sa Kurita's Orion leading less than a company of active Legion 'Mechs, she ordered an artillery strike to bring it down, confident she had finally succeeded in her mission. She was surprised to find that the 'Mech was actually piloted by Sho-saEsau Olivares, the Legion's first battalion commander. The entire defense was planned to buy Theodore Kurita enough time to escape Marfik on a DropShip disguised with Lyran colors.[19][20] Heany and the Fourth Skye Rangers had successfully taken Marfik, but it had taken weeks longer than expected and, more importantly, they had failed to capture or kill Theodore Kurita.

Colonel Randolph J. Thompson of the Thirteenth Assault Regiment was furious about Heany's tactics and the losses she caused to his third battalion in the Gether's Jewel incident. Acting under the orders of General Nondi Steiner, he held Heany and several of her command staff under house arrest pending an inquiry for a time.[21] The outcome is unknown, but apparently had no adverse effect on Heany's career.

In the follow up attacks, the Fourth split into two groups. First and Third Battalions invaded Kimball II, but were unexpectedly opposed by the 3rd Dieron Regulars. Second Battalion and the attached Lightning Company struck at Komephoros, where they were attacked by the 17th Benjamin Regulars. Although they held their own on both fronts, being split up and outnumbered demoralized the Fourth Rangers.[22]

This was the status quo when the war went into a "lull", an unofficial cease-fire that saw fighting even on contested planets reduced to a stand-still. The Fourth Skye took full advantage of the lull, resting up and preparing new battle plans. By the time the lull ended, the Fourth Skye Ranger elements on Kimball II were ready to take full advantage, going on the offensive and driving the Kurit troops back. On Komephoros, the Rangers managed to push the Seventeenth from their defensive positions, taking the advantage. Despite superior numbers, both Kurita regiments withdrew from their worlds in late July,[23] and were eventually rerouted to participate in Operation Contagion, an attempted counter-assault against the Commonwealth.

Despite the strong overall performance of the Fourth during the war, Heany's failure to capture Theodore Kurita would reflect on her for the rest of her career, and she would never again serve as a regular field commander. The scathing critique by Colonel Thompson regarding the Gether's Jewel debacle may also have played a part in this.

Although Heany's career survived the debacle on Marfik, her time commanding a front-line unit was over. She would serve on Nondi Steiner's staff for several years, but continued to develop a very poor reputation among AFFS officers who served under her, who found her orders to be incompetent and who usually requested a transfer as soon as possible.[24] Even Heany recognized that she had been relegated in her new position, given hollow honors and promotions. She deeply resented younger LCAF officers coming through the ranks who favored innovative approaches and other "Davionist" thinking, favored even by Nondi Steiner.[25]

In 3039, Hanse Davion finally launched a joint invasion of the Draconis Combine, looking to permanently destroy the Dragon. After a wildly successful first wave, General Nondi Steiner held a meeting of her command staff—including Heany—on 12 July on Vega to announce the second wave of the Lyran thrust, dubbed Operation WINTERSCHNEE. The meeting was attacked by DEST commandos acting under a plan conceived by Ninyu Kerai Indrahar. The special forces operatives killed many of the best young officers present and seriously injured others including General Steiner, who was sidelined for the remainder of the war. Heany, who saved Steiner's life during the incident, escaped with a leg injury. Realizing that she was the ranking officer present and active, Heany took command of the Lyran portion of the offensive.[26][27] Heany resorted to her traditional Lyran "frontal assault" tactics and the offensive stalled, with Combine counter-attacks threatening Lyran gains.[28] Heany's troops soon found themselves on the defensive, having lost the initiative.[29]

The attacks by the DEST and the ISF had also crippled Vega's communications network. When the 2nd Legion of Vega, reinforced by elements of the 14th Legion of Vega arrived, the defending Lyran forces consisted of the 3rd Davion Guards and the mercenary groups Snord's Irregulars and the Grave Walkers' First Regiment. Altough possessing an edge in numbers, complete lack of coordination on the part of the allied forces and Heany's incompetent leadership and strategy allowed the attackers to make planetfall. When the 2nd Dieron Regulars arrived to reinforce the Combine troops, the odds were suddenly even, and the Allies were no better coordinated. The DCMS forces were supported by twenty conventional regiments, while Heany made poor use of her own armor and infantry forces.[30] Brevet-Marshal James Seymour of the Third Davion Guards strongly advised Heany to stage a mobile defense, properly utilizing the combined-arms tactics that had been proven so effective.[31] Heany rejected his advice, choosing to meet the "Pride of Shionoha" of the Second Dieron in a frontal assault. Outmaneuvered in the field, the Allies slowly gave ground. Snord's Irregulars, cut off from their allies, left the planet, retreating back into the Commonwealth. By August 9, the Grave Walkers had also evacuated the planet with heavy losses. Outnumbered nearly three-to-one and demoralized under Heany's overall command, the Third Davion Guards continued to resist for three more days before Heany finally ordered the retreat.[30] Heany later tried to blame the debacle on the Grave Walkers and Irregulars, but a review by the MRBC cleared them of wrong-doing, and both commands remained in Lyran employ.[32]

By 3050, Heany held the rank of Hauptmann General in the new AFFC, and was MarshalSpiro Fairchild's second-in-command of the Accrington Command in the Skye March.[33] Although a high-ranking assignment, Heany's lack of a field command may have been a reflection of her past failures. In the aftermath of the Clan Invasion and the subsequent reorganization of the AFFC, Heany was placed in command of the Accrington Command as early as 3054.[34] She was not, however, promoted to the rank of Marshal, which was the traditional rank for a province commander at the time.

Kathleen Heany was described as capable in military administration with the ability to motivate her troops. However, she was staunchly "old school" Lyran in her approach, and rejected all attempts at using more innovative tactics,[39] particularly advice coming from Davion officers. Indeed, her reputation for prejudice against AFFS personnel and units followed her long after the Fourth Succession War, and eventually led to her enthusiastically placing her loyalty with Katherine Steiner-Davion.[24]

Even before the alliance with the Federated Suns, Heany seemed to hold an unhealthy prejudice against Nagelring graduates, probably a carry-over from old school rivalries turned into career elitism (being a Sanglamore graduate herself).[40] Heany also seemed to have been particularly religious, to the point where she regarded her assumption of command on Vega as a form of divine intervention.[41]Caradoc Trevena, one of the most respected strategists of the 3060s, was one of many who categorized Heany's general demeanor as "arrogant" when writing his acclaimed treatise on the War of 3039.[42]

Within the novel Heir to the Dragon it is strongly implied that Heany's own Atlas was part of a lance that was ambushed on Marfik by Kurita forces.[47] However, the scenario from BattlePack: Fourth Succession War recreating the ambush establishes one Hauptmann George Carlson piloting the Atlas. It may have been Heany's own 'Mech piloted by a subordinate in that particular incident.

Various publications give Heany the rank of Hauptmann-Kommandant (or senior battalion commander) at the time of the invasion of Marfik.[4][47] This appears to be an error, as it does not match more prevelant publications and an officer of such a rank would be unlikely to command a regiment, much less an elite 'Mech regiment reinforced by dozens of conventional regiment.